Abstract : 3M.3
Precipitation and river quality at the highest part of the Vitosha mountain

Stefka Blaskova, Liliana Iordanova
Stefka.Blaskova@meteo.bg
National Institute of Meteorology and Hidrology

Vitosha Mountain is situated near the city of Sofia - capital of the Republic of Bulgaria. The mountain has volcanic origin and its slopes are covered with granite and syenite rocks. At Cherni vruh (2290 m) is situated a synoptic station operating since 1935.

The results of the precipitation and river water quality analysis in the highest part of the mountain are presented. The precipitation quality data are collected at the Cherni vruh station, likewise pertaining to the precipitation chemistry network. The river water quality data were gathered throughout 2004 to 2006 when a local seasonal monitoring is carried out.

The following water quality parameters were analyzed: for the precipitations - pH, nitrates (NO3-), sulfates (SO42-); for the river water - pH, parameters of oxygen regime and organic content - dissolved oxygen (Î2), permanganate oxidation, biogenic elements – nitrates (NO3-), nitrites (NO2), ammonium (NH4+), phosphates (PO43-), total iron (Fe); parameters of mineral content - hydrocarbonates (HCO3-), sulfates (SO42-), chlorides (Cl), calcium (Ca2+), manganese (Mg2+), sodium and potassium (Na++K+).

The findings present the background levels of the studied hydrochemical parameters. The predominant anions in river water are hydrocarbonates (HCO3-) and sulfates (SO42-) while the predominant cations are calcium (Ca2+) and sodium (Na+). The measured pH values suggest the pure precipitation’s influence on river water in terms of acidity. It is perceivable that the majority of the nitrate concentrations in river water originate in the precipitations.